The present invention relates to photometric analysis apparatus of the type which uses disk-shaped rotors, in which the rotors are loaded automatically.
Photometric analysis apparatus using disk-shaped rotors is widely known. The disk-shaped rotors, which are generally made of plastics material, comprise a plurality of cuvettes arranged radially around a central hole. The cuvettes provide a plurality of communicating chambers separated by partitions. The rotor is connected to a hub connected to a motor which imparts rotary motion to the rotor. A sample to be analyzed and the appropriate reagents are introduced into each cuvette. The reagents are mixed by centrifugal effect when the rotor reaches a predetermined speed of rotation. In the next step, the individual cuvettes are brought sequentially into alignment with optical analysis means by programmed rotation of the rotor.
The general structure of the rotors and of the photometric analysis apparatus is known per se and will therefore not be described in greater detail herein. The function of the rotors and the way in which they interact with the sensors for analyzing the samples are described, for example, in the Applicant""s Italian patent application No. 20560A/83.
This photometric analysis apparatus is arranged to perform a large number of analyses in sequence. Clearly therefore, an essential characteristic of these machines is speed of operation. However, speed of operation must be combined with considerable precision in the execution of all of the steps of the analysis process from the loading of the rotors to their positioning on the hub, and to the perfect alignment of the cuvettes with the optical analysis means. A perfect and repeatable relationship between the positions of the cuvette and of the photoanalysis means is in fact essential for the reliability of the measurement.
The problem upon which the present invention is based is that of providing analysis apparatus having an automatic rotor-loading system which permits fast and accurate operation.
This problem is solved by photometric analysis apparatus and by a rotor as claimed in the appended claims.